Boundary in South America. 41 



laid emphasis on the existence of a great hiatus between 

 the Cretaceous and Tertiary, with special reference to 

 the Seymour and Cockburn Islands. There as well as in 

 Fireland, the great hiatus, at least in part, corresponds 

 to the San Jorge and thus indicates the bounding con- 

 tinental area. 



Consequently, we must infer, that in accordance with 

 the general strike of the southern Cordillera, the coast 

 of the San Jorge from the southern Santa Cruz took a 

 decidedly easterly direction. The southern point of 

 South America and the Falkland Islands were not reached 

 by this transgression. At present nothing can be said 

 about the extension into far southern regions, but the 

 results of future Antarctic expeditions are awaited. It 

 is interesting to see, that the eastern or southeastern 

 course of this coast seems to parallel the line of the 

 so-called " Southern Antilles" in the sense of Arctow- 

 sky and Suess ; but it would be hasty to draw any further 

 inferences. 100 



Thus, according to the foregoing explanations, the San 

 Jorge- Sea is directly traced from the 33rd to the 52nd 

 degree S. L. Apart from the brackish deposits in the 

 intermountain troughs between Sierra Famatina and 

 Sierra Velasco, which may have been connected with the 

 Alto Pencoso at the foot of the Sierra of San Luis, we 

 do not know any deposits of this epoch from the central 

 or northern Argentina. It is not possible to decide, 

 whether the brackish sediments with Cyrena, Corbicula 

 etc. of Santa Maria in the Province of Catamarca 

 can be correlated with the transgression of the San 

 Jorge-Sea. 101 But a priori it is not improbable that 

 future investigations may show more deposits of this 



Argentine) are found sheets and dikes of diorite separating the Upper 

 Cretaceous from the Lower Tertiary. 



99 Die geologisehen Beziehungen zwisehen Siidamerika und der angrenzen- 

 den Antarktis. Compte rendu de la Xl-eme Session Congres Geologique 

 Internationale, p. 759, Stockholm, 1910. 



100 Observations sur 1 'interet que presente 1 'exploration geologique des 

 Terres Australes, Bull. Soc. Geol. (3), 23, pp. 589 etc., 1895. See also: 

 J. G. Andersson, On the geology of Grahams Land. Bull. Geol. Inst., Upsala, 

 1906. — Wilckens, Zur Geologie der Siidpolarlander, Centralblatt f. Min. etc., 

 pp. 173 etc., 1906. — Suess, Antlitz der Erde, III, pp. 552 etc. — Becently 

 F. Kiihn (El arco de las Antillas Australes, Anales Museo Naeional de 

 Buenos Aires, 28, pp. 391 etc., 1916) has given a summary of this question. 



101 See Stelzner, Beitrage zur Geologie der Argentinischen Bepublik, p. 

 126, Cassel und Berlin, 1885. — -See also J. Bassmuss, Basgos geologicos 

 generates de las Sierras Pampeanas, Boletin 13B, Direccion Gral. de Minas 

 etc., Buenos Aires, 1916. 



